Inductively coupled electrosurgical instrument

ABSTRACT

In the present invention, a cordless inductively coupled electrosurgical instrument is adapted to receive electrosurgical energy from a specially designed trocar or trocar adapter. In one embodiment of the present invention, an electrosurgical instrument includes a handle, an elongated tube and an electrosurgical end effector. The handle may include an actuator such as a trigger which is operatively connected to the end effector through the elongated tube. The elongated tube may be, for example, a closure tube which is adapted to close the end effector when the handle actuator is moved. The electrosurgical end effector is adapted to apply electrosurgical energy to biological tissue in order to effect treatment of the tissue. The elongated closure tube includes one or more inductor coils adapted to couple electrosurgical energy to the end effector. The one or more inductor coils are electrically connected to the end effector through one or more electrical conductors.

This is a Continuation of application Ser. No. 08/885,517, Filed Jun.30, 1997, now U.S. Pat. No. 5,849,020.

This application is related to the following copending applications:application Ser. No. 08/856,534 filed May 14, 1997 which was issued asU.S. Pat. No. 5,984,921 Nov. 16, 1999; application Ser. No. 08/877,715,filed Jun. 18, 1997 which was issued as U.S. Pat. No. 5,961,514 on Oct.5, 2001; application Ser. No. 08/878,421, filed Jun. 18, 1997 which hasissued as U.S. Pat. No. 5,925,041 on Jul. 20, 1999; application Ser. No.08/885,458, filed Jun. 30, 1997 which has issued as U.S. Pat. No.6,106,519 on Aug. 22, 2000; application Ser. No. 08/884,949, filed Jun.30, 1997 which has issued as U.S. Pat. No. 5,951,552 on Sep. 14, 1999;and application Ser. No. 08/885,166, filed Jun. 30, 1997, which asissued as U.S. Pat. No. 5,916,215 on Jun. 29, 1999.

FIELD OF THE INVENTION

The present invention relates, in general, to an improvedelectrosurgical instrument and method of use and, more particularly, toan inductively coupled cordless electrosurgical instrument adapted toreceive electrosurgical energy from a specially adapted electrosurgicaltrocar.

BACKGROUND OF THE INVENTION

The surgical trocar has become the mainstay in the development andacceptance of endoscopic surgical procedures. Endoscopic surgeryinvolves the performance of surgery through a number of openings havinga relatively small diameter. These openings are made with the trocar,which typically includes a trocar obturator and a trocar cannula. Theobturator is the piercing implement which punctures the body wall tomake the opening. Once the puncture is made, the obturator is withdrawnfrom the cannula. The cannula then provides a small diameter passagewayinto and through the body wall to provide access for additional surgicalinstrumentation to the surgical site. The function, structure andoperation of a typical trocar is described in detail in U.S. Pat. No.5,387,197, which is hereby incorporated herein by reference.

Such additional surgical instruments may include, for example, bipolaror monopolar electrosurgical instruments which utilize radio frequencyelectrosurgical energy. Known electrosurgical instruments include, forexample, bipolar forceps, bipolar scissors, monopolar-hooks,monopolar-scissors and bipolar endocutters. Each of those instrumentshas an electrosurgical end effector which is adapted to treat tissuethrough the application of electrosurgical (e.g. radio frequency or RF)energy to tissue which is brought in contact with the electrosurgicalend effector. Most known electrosurgical instruments are connected byelectrical cords to electrosurgical generators. The structure andoperation of a typical mechanical cutter/stapler is described in U.S.Pat. No. 5,597,107 which is hereby incorporated herein by reference. Thestructure and operation of a typical bipolar cutter/stapler (“bipolarendocutter”) is described in U.S. Pat. No. 5,403,312 which is herebyincorporated herein by reference.

Electrosurgical generators, such as the Force II generator (which isavailable from Valleylab of Bolder Colo.), supply electrical energy toknown electrosurgical instruments through electrical cords. Theelectrical cords, being attached directly to the electrosurgicalinstrument, may make the electrosurgical instrument inconvenient to use.Alternatively, electrical cords may cause undesirable delays as oneelectrosurgical instrument is unplugged from the generator and anotheris plugged in. Thus, it would be advantageous to design a cordlesselectrosurgical instrument such as a cordless instrument whereinelectrosurgical energy is inductively coupled to the instrument.However, such a cordless electrosurgical instrument would have to beconnected to the electrosurgical generator through some alternatearrangement. Therefore, it would also be advantageous to design a trocaror a trocar adapter which is adapted to inductively coupleelectrosurgical energy to specially designed cordless electrosurgicalinstruments. It would further be advantageous to design a cordlesselectrosurgical instrument and electrosurgical trocar or trocar adapterwherein the electrosurgical energy is inductively coupled from theelectrosurgical trocar to the cordless electrosurgical instrument whenelectrosurgical energy is applied to the electrosurgical trocar ortrocar adapter.

SUMMARY OF THE INVENTION

In the present invention, a cordless inductively coupled electrosurgicalinstrument is adapted to receive electrosurgical energy from a speciallydesigned trocar or trocar adapter. In one embodiment of the presentinvention, an electrosurgical instrument includes a handle, an elongatedtube and an electrosurgical end effector. The handle may include anactuator, such as a trigger, which is operatively connected to the endeffector through the elongated tube. The elongated tube may be, forexample, a closure tube which is adapted to close the end effector whenthe handle actuator is moved. Alternatively, the closure tube mayinclude a mechanism connecting the handle actuator to the end effector,which mechanism acts to close the end effector when the handle actuatoris moved. The electrosurgical end effector is adapted to applyelectrosurgical energy to biological tissue in order to effect treatmentof the tissue. The elongated closure tube includes one or more inductorcoils adapted to couple electrosurgical energy to the end effector. Theone or more inductor coils are electrically connected to the endeffector through, for example, one or more electrical conductors.

In one embodiment of the present invention, the elongated closure tubeis electrically conductive and is electrically connected to one end ofthe inductor coils and to one of the electrodes on the end effector. Theopposite end of the inductor coil is connected to the opposing electrodeon the end effector such that, when the end effector is used to graspelectrically conductive material (e.g. biological tissue), the electriccircuit within the instrument is complete and electrical current canflow through the inductor coil and the biological tissue. In a furtherembodiment of the invention, the closure tube may be covered by anelectrically insulating material.

In a further embodiment of the present invention, the electrosurgicalinstrument according to the present invention is adapted to fit througha trocar which includes an electrosurgical adapter. The electrosurgicaladapter includes an elongated aperture with one or more inductor coilspositioned around the aperture of the adapter and extending axiallyalong the elongated aperture, at least a first electrical conductor, anouter housing and an electrical cord connected to the first conductor.

In a further embodiment of the present invention, the closure tube ofthe inductively coupled electrosurgical instrument is constructed, atleast in part, of a ferromagnetic material, which may be, for example,iron. The adapter wall may alternatively be constructed of any materialhaving a high relative magnetic permeability, that is, a permeability ofgreater than 100.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. The invention itself, however, both as toorganization and methods of operation, together with further objects andadvantages thereof, may best be understood by reference to the followingdescription, taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of an inductive electrosurgical trocaraccording to the present invention.

FIG. 1A is a perspective view of an inductive electrosurgical trocarincluding a portion of the closure tube of an inductive electrosurgicalinstrument according to the present invention wherein the closure tubeis shown positioned in the central aperture of the inductiveelectrosurgical trocar.

FIG. 2 is a plan view section taken along 2—2 in FIG. 1 through theproximal end of the inductive electrosurgical trocar illustrated in FIG.1.

FIG. 2A is a plan view section taken along 2A—2A in FIG. 1A through theproximal end of the inductive electrosurgical trocar and closure tubeillustrated in FIG. 1A.

FIG. 3 is a perspective view in plane section of inductiveelectrosurgical adapter illustrated in FIG. 1.

FIG. 3A is a perspective view in plane section of the inductiveelectrosurgical adapter and closure tube illustrated in FIG. 1A.

FIG. 4 is a perspective view of a cordless inductive electrosurgicalinstrument according to the present invention.

FIG. 5 is an exploded perspective view of the distal end of a cordlessinductive electrosurgical instrument according to the present invention.

FIG. 6 is a cut away view of the handle portion of the electrosurgicalinstrument illustrated in FIG. 4.

FIG. 7A is a cutaway view of the end effector of the inductiveelectrosurgical instrument illustrated in FIG. 4.

FIG. 7B is a cutaway view of a central portion of the closure tube ofthe inductive electrosurgical instrument illustrated in FIG. 4.

FIG. 7C is a cutaway view of a proximal portion of the of the closuretube of the inductive electrosurgical instrument illustrated in FIG. 4.

FIG. 8 is a schematic diagram graphically illustrating the inductivecoupling between an inductive electrosurgical trocar or trocar adapterand an inductive electrosurgical instrument according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of an inductive electrosurgical trocar 11.FIG. 1A is a perspective view of inductive electrosurgical trocar 11including a portion of closure tube 50 of inductive electrosurgicalinstrument 16 according to the present invention. Inductiveelectrosurgical trocar 11 includes trocar cannula 8 and a inductiveelectrosurgical adapter 14. Inductive electrosurgical trocar 11 may alsoinclude an obturator assembly (not shown) such as the one illustrated inU.S. Pat. No. 5,387,197, which has been previously incorporated hereinby reference. Trocar cannula 8 includes cannula housing 12 and cannulatube 10, extending from cannula housing 12. Inductive electrosurgicaladapter 14 includes an adapter housing 15, locking connector 17, centralaperture 19, strain relief 23 and an electric cord 18. Inductiveelectrosurgical adapter 14 is connected to trocar cannula 8 by lockingconnector 17. Locking connector 17 includes locking cleats 20 andrelease buttons 22. It will be apparent that inductive electrosurgicaladapter 14 may be integrated directly into trocar cannula housing 12,thus eliminating the need for locking connector 17.

FIG. 2 is a plan view section taken along 2—2 in FIG. 1 of the proximalend of inductive electrosurgical trocar 11. FIG. 2A is a plan viewsection taken along 2A—2A in FIG. 1A of the proximal end of inductiveelectrosurgical trocar 11 and a portion of closure tube 50 of inductiveelectrosurgical instrument 16. In FIGS. 2 and 2A, cannula housing 12includes flapper valve 34, valve spring 35 and ring gasket 33. Inductiveelectrosurgical adapter 14 includes central aperture 19, front flange 25and base flange 24. Central aperture 19 is an elongated aperture forreceiving working instruments such as endoscopic electrosurgicalinstruments. Inductive electrosurgical adapter 14 further includes aninductor which, in the embodiment illustrated in FIGS. 2-3, comprisesinductor coil 91, proximal inductor lead 93 and distal inductor lead 94.At least a portion of the wall of central aperture 19 is formed byinterior wall 92 which may be formed of, for example, an insulatingmaterial to insulate inductor coil 91 from central aperture 19.Alternatively, interior wall 92 may be formed of, for example, aferromagnetic material such as, for example, iron. Interior wall 92 ispositioned against and held in place by front flange 25 and base flange24. A compression member (not shown) such as, for example, an o-ring,may be positioned around interior wall 92 to bias interior wall 92toward the center of central aperture 19. As illustrated in FIGS. 1, 1A,2 and 2A, Electric cord 18 passes through strain relief 23 and ismechanically and electrically connected to upper conductor 36 and lowerconductor 38. Upper conductor 36 is electrically connected to proximalinductor lead 93 by proximal connector 95. Proximal inductor lead 93 iselectrically connected to the proximal end of inductor coil 91. Lowerconductor 38 is electrically connected to distal inductor lead 94 bydistal connector 96. Distal inductor lead 94 is electrically connectedto the distal end of inductor coil 91. The portion of inductiveelectrosurgical instrument 16 illustrated in FIG. 2A includes closuretube 50, instrument inductor coil 46, channel retainer 86 and cartridgechannel 88. Latch detents 4 in cannula housing 12, are adapted toreceive locking cleats 20 of locking connector 17.

FIG. 3 is a perspective view in plane section of inductiveelectrosurgical adapter 14. FIG. 3A is a perspective view in planesection of inductive electrosurgical adapter 14 and a portion of closuretube 50 of inductive electrosurgical instrument 16. Referring now toFIGS. 2-3 and 2A-3A and particularly to FIGS. 3 and 3A, inductiveelectrosurgical adapter 14 includes adapter housing 15, locking cleats20, central aperture 19, inductor coil 91, locking connector 17,interior wall 92, aperture interior surface 21, base flange 24, frontflange 25 and release buttons 22. Electrosurgical energy is supplied toinductive electrosurgical adapter 14 by electric cord 18 which isconnected to bipolar electrosurgical plug 64. Thus, electrosurgicalenergy may be coupled from bipolar electrosurgical plug 64 throughelectric cord 18 to inductor coil 91. Central aperture 19 is defined byaperture interior surface 21. The portion of aperture interior surface21 visible in FIGS. 2, 2A, 3 and 3A is formed, at least in part, by theinterior surface of interior wall 92. Strain relief 23 protects electriccord 18 as it passes through adapter housing 15.

FIG. 4 is a perspective view of a inductive cordless electrosurgicalinstrument 16 which may be, for example, a bipolar cutter/stapler. InFIG. 4, inductive electrosurgical instrument 16 includes handle 72,closure tube 50 and end effector 57, which, in the embodiment of theinvention illustrated in FIG. 4, is a bipolar cutter/stapler. Alternatebipolar end effectors may include: a bipolar forceps such as the forcepsillustrated in U.S. Pat. No. 5,540,684 a bipolar cutting an coagulationinstrument such as the tissue cutting forceps illustrated in U.S. Pat.No. 5,445,638; a bipolar scissors such as the shears illustrated in U.S.Pat. No. 5,352,222; or a bipolar probe such as the probe illustrated inU.S. Pat. No. 5,342,357. U.S. Pat. Nos. 5,540,684 5,445,638, 5,352,222and 5,342,357 are hereby incorporated herein by reference. Closure tube50 is elongated to facilitate insertion of end effector 57 through atrocar cannula, thus facilitating the use of inductive electrosurgicalinstrument 16 in endoscopic or laparoscopic surgical procedures. Closuretube 50 may be any appropriate shape, including, for example, anelongated square or triangular tube. Handle 72, which is located at theproximal end of inductive electrosurgical instrument 16, includesgrasping trigger 74, firing trigger 76 and release trigger 78. Closuretube 50, which connects handle 72 to end effector 57, includes rotationknob 70. End effector 57, which is located at the distal end of closuretube 50 includes anvil 58, cartridge channel 88 and staple cartridge 68.Inductive electrosurgical instrument 16 is similar in structure andoperation to the bipolar endoscopic electrocautery linear cutting andstapling instrument illustrated and described in U.S. Pat. No.5,403,312, which has been previously incorporated herein by reference.However inductive electrosurgical instrument 16 is cordless andelectrosurgical energy is inductively coupled into electrosurgicalinstrument 16. In inductive electrosurgical instrument 16,electrosurgical energy is supplied to end effector 57 through one ormore inductor coils which may be located in, for example, closure tube50.

FIG. 5 is an exploded perspective view of the distal end of anelectrosurgical instrument according to the present invention, such aselectrosurgical instrument 16. In FIG. 5, outer tube 51 may bepositioned over closure tube 50. In the instruments illustrated in FIG.5, closure tube 50 is electrically conductive and outer tube 51 isconstructed of an electrically insulating material. Closure tubeconnector 44 of closure tube 50 is electrically connected to instrumentproximal inductor lead 42, which is electrically connected to theproximal end of instrument inductor coil 46. The distal end ofinstrument inductor 46 is electrically connected to electrical conductor48 through instrument distal connector 45. In the embodiment of FIG. 5,electrical conductor 48 electrically couples instrument coil 46 toelectrode assembly 52, which is positioned on anvil 58. Electricallyconductive closure tube 50, in turn, electrically couples the proximalend of instrument coil 46 to cartridge channel 88 which, in theembodiment of the invention illustrated in FIGS. 4 and 5 is electricallyconductive and acts as a return electrode. In an alternateelectrosurgical instrument, instrument proximal inductor lead 42 couldbe connected to a second electrode on end effector 57 by an insulatedwire which runs through closure tube 50 and, in such an instrument,closure tube 50 may be constructed of an insulating material. Electrodeassembly 52 is positioned in anvil 58. Electrode assembly 52 may beelectrically insulated from anvil 58 and closure tube 50 to preventelectrode assembly 52 from shorting to anvil 58 or closure tube 50.Conductor 48, instrument inductor coil 46, instrument proximal inductorlead 42, instrument distal inductor lead 43 and instrument distalconnector 45 may also be insulated to prevent them from shorting toclosure tube 50 or any of the mechanisms in closure tube 50.

FIG. 6 is a cut away view of the handle of electrosurgical instrument 16which is illustrated in FIG. 4. In FIG. 6, handle 72 includes grip 62,grasping trigger 74 and firing trigger 76. Pivotal movement of graspingtrigger 74 results in distal movement of yoke 63 and closure tube 50,closing anvil 58 against staple cartridge 68. Staple cartridge 68 ispositioned in cartridge channel 88. Pivotal movement of grasping trigger74 further releases firing rod 84 and positions firing trigger 76 toengage drive member 67. Further pivotal movement of firing trigger 76toward grip 62 results in distal movement of drive member 67 whichrotates multiplier 66 in a counterclockwise direction. Counterclockwiserotation of multiplier 66 results in distal movement of firing rod 84which, in the embodiment of the invention illustrated herein, fires thestaples in staple cartridge 68.

FIG. 7A is a cutaway view of end effector 57 of inductive cordlesselectrosurgical instrument 16. FIG. 7B is a cutaway view of a centralportion of closure tube 50 of inductive cordless electrosurgicalinstrument 16. FIG. 7C is a cutaway view of a proximal portion of the ofthe closure tube of inductive electrosurgical instrument 16. In theembodiments of electrosurgical instrument 16 illustrated in FIGS. 7A-7C,anvil base 73 of Anvil 58 supports electrode assembly 52 and includesanvil guide 65 and staple forming slots (not shown). Electrode assembly52 is electrically coupled to electrical conductor 48 and to anvilelectrodes 55. Anvil base 73 is insulated from electrode assembly 52 byanvil insulator 59. Electrical conductor 48 is electrically connected toinstrument inductor coil 46 by instrument distal connector 45 andinstrument distal inductor lead 43. Instrument inductor coil 46 ispositioned in the central portion of closure tube 50. Cartridge channel88 of end effector 57 supports staple cartridge 68, wedge guide 80 andwedge block assembly 82. Cartridge channel 88 extends into and, beingconstructed of electrically conductive material in the embodimentillustrated in FIG. 7, is electrically coupled to electricallyconductive closure tube 50. Closure tube 50 is electrically coupled tothe proximal end of instrument inductor coil 46 by closure tubeconnector 44 and instrument proximal inductor lead 42. Thus, cartridgechannel 88 may provide a return path for electrical energy coupled toanvil electrodes 55 of end effector 57 when end effector 57 is used tograsp tissue or other electrically conductive material which touchesboth cartridge channel 88 and anvil electrodes 55. Electrosurgicalenergy coupled to cartridge channel 88 may be coupled back toelectrosurgical trocar 11 through instrument inductor coil 46. Closuretube 50 may be electrically insulated from surrounding structures ortissue by, for example, covering closure tube 50 with a sleeve ofelectrically insulating material 51. Closure tube 50 also supports andencloses the proximal end of anvil 58, the proximal end of cartridgechannel 88, firing rod 84, the proximal end of knife 90, channelretainer 86 and at least a portion of wedge block assembly 82 and wedgeguide 80. Closure tube 50 may also be constructed of a ferromagneticmaterial such as, for example, iron, to facilitate magneting couplingbetween inductor coil 91 in inductive electrosurgical trocar 11 andinstrument inductor coil 46 in inductive electrosurgical instrument 16.Anvil 58 opens and closes by, for example, pivoting around one or morepivot pins 60.

In the cordless electrosurgical instruments illustrated in FIGS. 4-7,knife 90 is connected to wedge assembly 82 and wedge assembly 82 isconnected to firing rod 84, which, in turn, is operatively connected tofiring trigger 76. Closure tube 50 is operatively connected to rotationknob 70, grasping trigger 74 and release trigger 78. Wedge guide 80 isfitted over wedge block assembly 82 to guide wedge block assembly 82 asfiring rod 84 moves wedge block assembly 82. The structure and operationof the mechanical features of inductive electrosurgical instrument 16may be better understood with reference to the mechanical cutting andstapling instrument illustrated and described in U.S. Pat. No. 5,597,107which is hereby incorporated herein by reference.

FIG. 8 is a schematic diagram graphically illustrating the inductivecoupling between inductive electrosurgical adapter 14 of inductiveelectrosurgical trocar 11 and inductive electrosurgical instrument 16.In FIG. 8, first output 6 of electrosurgical generator 5 is electricallyconnected to a first end of inductor coil 91 through electric cord 18,upper conductor 36, proximal connector 95 and proximal inductor lead 93.Upper conductor 36 is electrically connected to electric cord 18. Secondoutput 7 of electrosurgical generator 5 is electrically connected to asecond end of inductor coil 91 through electric cord 18, lower conductor38, distal connector 96 and distal inductor lead 94. Lower conductor 38is electrically connected to electric cord 18. When end effector 57 isclosed around electrically conductive material such as biological tissuewhich is also in contact with cartridge channel 88, the electricalcircuit from instrument proximal inductor lead 42 of instrument inductorcoil 46 to instrument distal inductor lead 43 of instrument inductorcoil 46 is completed through closure tube connector 44, electricallyconductive closure tube 50, cartridge channel 88, the conductivematerial being grasped, anvil electrodes 55 of electrode assembly 52,electrical conductor 48, instrument distal connector 45 and instrumentdistal inductor lead 43. Thus, with end effector 57 closed aroundconductive material and electrosurgical generator 5 turned on,electrosurgical energy, such as electrical current at a suitable outputfrequency and power, passes from electrosurgical generator 5, throughinductor coil 91 (which is electromagnetically coupled to instrumentinductor coil 46) through instrument inductor coil 46, to end effector57 and returns through instrument inductor coil 46 and inductor coil 91back to electrosurgical generator 5.

As FIG. 8 schematically illustrates, instrument inductor coil 46 iselongated so that movement of inductive electrosurgical instrument 16 incentral aperture 19 does not result in loss of electromagnetic couplingbetween inductor coil 91 and instrument inductor coil 46. Thus, even asinductive electrosurgical instrument 16 is moved within inductiveelectrosurgical trocar 11 to facilitate treatment of the patient,inductive coupling between inductor coil 91 and instrument inductor coil46 may be maintained. It may also be advisable, in certain situations,to include one or more matching capacitors (not shown) in eitherinductive electrosurgical trocar 11 or in inductive electrosurgicalinstrument 16 to electrically match inductive electrosurgical instrument16 to inductive electrosurgical trocar 11 in order to increase the powercoupled to tissue grasped by end effector 57. In particular, such amatching capacitor(s) (not shown) would be selected to make the loadrepresented by the trocar, instrument and tissue appear to besubstantially resistive at the frequency of interest (e.g. the frequencyat which the electrosurgical energy is being transmitted to the tissue).

In operation, trocar cannula 8 is used with a conventional trocarorbitor (not shown) to penetrate the wall of a body cavity such as, forexample, the abdominal wall of a human being. After the body wall ispenetrated, the obturator assembly is withdrawn from trocar cannula 8,and the cannula is used as an access portal for the passage of variousendoscopic instruments to provide, for example, access to the internalorgans of a human being. Where the endoscopic instrument to be used is acordless inductive electrosurgical instrument such as electrosurgicalinstrument 16, inductive electrosurgical adapter 14 may be attached tocannula housing 12 of trocar cannula 8 using, for example, lockingconnector 17. Once inductive electrosurgical adapter 14 is attached totrocar cannula 8 and electric cord 18 is attached to a suitableelectrosurgical generator (such as generator 5 in FIG. 8), inductiveelectrosurgical trocar 11 may be used to provide electrosurgical energyto cordless inductive electrosurgical instruments such aselectrosurgical instrument 16. When a cordless inductive electrosurgicalinstrument such as electrosurgical instrument 16, is inserted into abody cavity through, for example, inductive electrosurgical trocar 11,end effector 57 passes through trocar cannula 8 and into the body cavitywhile most of closure tube 50 remains in the trocar. Handle 72, which isoutside of inductive electrosurgical trocar 11, may be manipulated bythe surgeon to control the position of end effector 57.

A cordless inductive bipolar electrosurgical instrument according to thepresent invention, such as electrosurgical instrument 16 of FIG. 7 maybe used by inserting the cordless instrument into an appropriateinductive electrosurgical trocar such as the electrosurgical trocarillustrated in FIG. 1. In the inductive electrosurgical trocarillustrated in FIG. 1, electrosurgical energy is provided to instrument16 by, for example, inductive electromagnetic coupling between inductorcoil 91 of inductive electrosurgical trocar 11 and instrument inductorcoil 46 of inductive electrosurgical instrument 16. The diameter ofcentral aperture 19 generally corresponds with the outer diameter ofclosure tube 50 so that closure tube 50 slides through central aperture19 and the interior of cannula tube 10. Efficient electromagneticcoupling should be maintained so long as at least a portion ofinstrument inductor coil 46 is positioned in central aperture 19opposite at least a portion of inductor coil 91. At least one of closuretube 50 and interior wall 92, may be preferably formed of aferromagnetic material, or any suitable material having a high relativemagnetic permeability, to facilitate and enhance electromagneticcoupling between inductive coil 91 and instrument inductor coil 46. Asindicated previously, a compression member (not shown) may be used tohelp to ensure that interior wall 92 and closure tube 50 maintain goodphysical contact, minimizing any air gap and enhancing inductivecoupling between the inductor coil 91 and instrument inductor coil 46.Electromagnetic coupling may also be enhanced by using multipleinductors or multiple coil layers in inductive electrosurgical trocar 11or in inductive electrosurgical instrument 16. With instrument inductorcoil 46 positioned opposite inductor coils 91, electrosurgical energymay be supplied to inductive electrosurgical instrument 16 throughelectric cord 18 and inductive electrosurgical trocar 11. In theembodiments of the invention illustrated herein, electrosurgical energysupplied to trocar 11 by electric cord 18 passes through conductors 36and 38 to inductor leads 93 and 94 and into inductive electrosurgicalinstrument 16 via electromagnetic coupling between inductor coils 91 andinstrument inductor coil 46. Electrosurgical energy supplied toinductive electrosurgical instrument 16 by electromagnetic couplingbetween 91 and 46 may be supplied to end effector 57 via the circuitformed by instrument distal inductor lead 43, instrument distalconnector 45, electrical conductor 48, electrode assembly 52, cartridgechannel 88, closure tube 50, closure tube connector 44 and instrumentproximal inductor lead 42. This circuit is completed when biologicaltissue or other conductive material is grasped by end effector 57,providing an electrical path from electrode assembly 52 to cartridgechannel 88. In the embodiment of inductive electrosurgical instrument 16illustrated and described herein, cartridge channel 88 and anvilelectrodes 55 are electrically conductive. Thus, where electrodeassembly 52 acts as a primary electrode, cartridge channel 88 acts as asecondary or return electrode. When electrically conductive tissue isgrasped by end effector 57 and an electrosurgical generator is connectedto inductor coil 91 and inductive electrosurgical instrument 16 ispositioned in inductive electrosurgical trocar 11 as described herein,electrosurgical energy will flow through the grasped tissue coagulatingor otherwise electrosurgically treating the grasped tissue. It may alsobe advantageous to provide one or more switches (not shown) to controlthe flow of electrosurgical energy to trocar 11 or to end effector 57 ofinductive electrosurgical instrument 16.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. Accordingly, it isintended that the invention be limited only by the spirit and scope ofthe appended claims.

What is claimed is:
 1. An electrosurgical instrument wherein saidelectrosurgical instrument comprises: a) a handle including an actuator;b) an end effector including first and second electrodes wherein saidend effector comprises a first grasping element and a second graspingelement; c) an elongated, electrically conductive tube having aninternal surface and an external surface, wherein said tube connectssaid end effector to said handle and includes a mechanism operativelyconnecting said end effector to said actuator; d) an inductor coilpositioned in said tube around said mechanism and extending along acentral axis of said tube; e) first and second conductors electricallyconnected to first and second ends of said inductor coil; f) said firstconductor being electrically connected to said elongated tube whereinsaid elongated tube is electrically connected to said first electrode;g) said second conductor being connected to a second electrical contact.2. An electrosurgical instrument according to claim 1 wherein saidelongated tube includes a ferromagnetic material.
 3. An electrosurgicalinstrument according to claim 1 wherein said elongated tube includes amaterial having a high relative magnetic permeability.